The first American conscientious objector from the Iraq war will give himself up at a marine base in California this morning. He said he believed the war was "immoral because of the deception involved by our leaders".

Stephen Eagle Funk, 20, a marine reserve who was due to be sent for combat duty, is currently on "unauthorised absence" from his unit. He faces a possible court martial and time in military prison for his action.

"I know I have to be punished for going UA," Mr Funk told the Guardian in an interview before surrendering to authorities, "but I would rather take my punishment now than live with what I would have to do [in Iraq] for the rest of my life. I would be going in knowing that it was wrong and that would be hypocritical."

Mr Funk, who is originally from Seattle and is half Filipino, was approached by a recruiting officer last year. At the time, he said, he was depressed after dropping out of a biology course at the University of Southern California in Los Angeles. He was working part-time for a vet and in a pet shop.

His family and friends were surprised by his decision, he said, because they had known him to have liberal political views and not to have been interested in the military.

"I wanted to belong and I wanted another direction in my life, and this seemed to offer it," said Mr Funk. "They told me I would be able to go back to school [university]." Recruits have their college fees paid once they complete their service.

"The ads make the armed forces look so cool - 'Call this number and we'll send you a free pair of boxer shorts' - and a lot of kids don't realise what's involved," he said. Although he graduated from the famously tough marine boot camp in San Diego and excelled as a rifleman during the 12-week induction period, Mr Funk said he had started to have doubts about military service during his training.

"Every day in combat training you had to yell out 'Kill! Kill!' and we would get into trouble if you didn't shout it out, so often I would just mouth it so I didn't get into trouble." The recruits were also encouraged to hurt each other during hand-to- hand combat training. "I couldn't do that so they would pair me up with someone who was very violent or aggressive."

Mr Funk said many recruits were envious of those who were being sent to the Gulf. "They would say things like, 'Kill a raghead for me - I'm so jealous.'"

As a Catholic who attended mass most Sundays during training, he eventually decided to take his concerns to the chaplain. "He said, 'It's a lot easier if you just give in and don't question authority.' He quoted the Bible at me and said, 'Jesus says to carry a sword.'

"But I don't think Jesus was a violent man - in fact, the opposite - and I don't think God takes sides in war _ Everyone told me it was futile to try to get out."

At shooting practice, although he scored well, the instructor told him he had an attitude problem: "I was a little pissed off and I said, 'I think killing people is wrong.' That was the crystallising moment because I had never said it out loud before. It was such a relief."

He became concerned about the reasons for the conflict in Iraq. "This war is very immoral because of the deception involved by our leaders. It is very hypocritical." He is opposed to the use of war as a way of solving problems.

"War is about destruction and violence and death. It is young men fighting old men's wars. It is not the answer, it just ravages the land of the battleground. I know it's wrong but other people in the military have been programmed to think it is OK."

Mr Funk, who is being counselled by conscientious objectors from the 1991 Gulf war, said he had gone public to try to dissuade other young people who had not thought through their reasons for joining the forces. "All they [the military] want is numbers. What I'm doing is really trying to educate people to weigh their options - there are so many more ways to get money for school."

He added: "My mum had a gut feeling it wouldn't work out." Although he does not know what punishment awaits, "it's a risk I'm willing to take".

This morning, accompanied by his lawyer and former conscientious objectors from previous wars, he will arrive at his home base in San Jose, change into his uniform and give himself up.